Immune-challenged vampire bats produce fewer contact calls

Abstract

Vocalizations are an important means to facilitate social interactions, but vocal communication may be affected by infections. While such effects have been shown for mate-attraction calls, other vocalizations that facilitate social contact have received less attention. When isolated, vampire bats produce contact calls that attract highly associated groupmates. Here, we test the effect of an immune challenge on contact calling rates of individually isolated vampire bats. Sickness behaviour did not appear to change call structure, but it decreased the number of contact calls produced. This effect could decrease contact with groupmates and augment other established mechanisms by which sickness reduces social encounters (e.g. mortality, lethargy and social withdrawal or disinterest).

Sickness and the Social Brain: How the Immune System Regulates Behavior across Species

“…In addition to humans, changes in social motivation in response to sickness have been described in many other animals. Social vocalizations in passerine birds [Garamszegi et al, 2004], field crickets [Jacot et al, 2004;Kelly and Leroux, 2020], and vampire bats [Stockmaier et al, 2020] have all been studied in the context of immune challenge. In all cases, infection causes a decrease in social contacts, which can be interpreted as social withdrawal.…”

“…Decreased social song production Decreased testosterone [Garamszegi et al, 2004] Field crickets LPS (10 mg/g) Decreased social calling rate Unknown [Jacot et al, 2004] Vampire bats LPS (5 mg/kg) Decreased social contact calls Unknown [Stockmaier et al, 2020] Devlin/Smith/Bilbo likely for LPS to cross the blood-brain barrier, it has been argued that this cytokine release by microglia could be one major way that experimental, non-central nervous system (CNS) infection impacts social behavior. Microglial function and social behavior are related, as a variety of disruptions to microglia function influence social behavior.…”

Love and fear in the times of sickness

“…Lipopolysaccharide-challenged female vampire bats still received the same amount of social grooming as their healthy conspecifics. However, the infected females engaged less often in allog-rooming [ 42 ] and produce fewer contact calls than healthy bats when isolated, thereby decreasing their probability of being met by conspecifics [ 43 ]. This decrease in vocalization emitted by sick individuals is observed in several species, especially in birds [ 14 ].…”

Sickness and the Social Brain: Love in the Time of COVID

“…Vocalizations are used by many species to communicate across social networks and to find and engage with potential mates. Such social contacts are reduced following LPS administration in passerine bird species ( 54 , 55 ), vampire bats ( 56 ), and field crickets ( 57 ), among others. Wild barn mice decrease their social contacts and limit the size of their social network following an LPS challenge ( 58 ).…”

“…Similarly, LPS administration increases social interaction and huddling in male and female rats ( 65 ) and enhances partner preference in female prairie voles ( 66 ). In vampire bats, LPS administration decreases social grooming between conspecifics, but this effect is minimal for maternal grooming of infants ( 56 ). Together, these findings indicate that changes in social behavior following infection are highly context- and social partner- specific.…”